Electric motor



(No Model.)

H. W.- SPANG.

. ELECTRIC MOTOR. No; 279,036. Patented June 5.1883.

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UNITED STATES PATENT OFFICE.

ELECTRIC MOTQR.

SPECIFIOATlION forming part of Letters Patent No. 279,036, dated June 5,1883.

Application filed March 12. 1883.

(No model.)

To aZZ whom it may concern Be it known that I, HENRY W. SPANG, a citizenof the-United States, residing at Readmg, in the county of Berks andState of Penn sylvania, have invented certain new and use fulImprovements in Electric Motors, and I do hereby declare the followingto be a full, clear, and exact description of the invention, referencebeing had to the accompanying drawings, which form part of thisspecification, in which the figure is a view illustrating an electromotor with my improvements applied thereto.

My invention has relation to electric motors, nd has reference to meansfor regulating, controlling, and varying the speed of the same bycutting out or shunting portions of the coils of the field magnet ormagnets, such means also comprising resistances introduced into theexternal circuit and equivalent to that cut out of the field, so as tomaintain a constant and unvarying resistance in the entire circuit,there by preventing reaction upon the generator and on themotor-armature and 011 other motors .where a number of the latter areemployed in series.

In an application for patent heretofore filed by me for improvements inelectromotors are shown and described means whereby portions of thecoils of the field-magnets may be cut out of circuit, thereby reducingthe energ of the magnet and. diminishing the speed of the armature. Ihave discovered that it is desirable when this cutting out or shuntingof a portion or portions of the field-magnet is accomplished tointroduce into the external circuit resistance equivalent to that of theportion or portions of the field-magnet cut out. By this means theresistance of the entire circuit is kept unvarying, so that uniformityof current may be maintained, and the reaction of an excess of our renton the generator and on the motor-armature, as well as upon other motorsin the same series where two or more are employed, be prevented.

My invention accordingly consists in the combination, with anelectromotor constructed or provided with a device whereby a portion orportions of the coils of its field magnet or magnets may be cut out orshunted, of means whereby external resistance the equivalent of that cutout of the field magnet or any known or suitable type of machine for thepurpose. In practice I prefer to employ a motor constructed with aring-armature and stationary field-magnets within the inductiveinfluence of a pole or the poles of which said armature is located androtates.

B represents a ring-armature, and C a field magnet having pole-piece, c,and helices e c c of insulated wire. If desired, there ma be two or morefield-magnets, and the armaonly one pole or in the fields of two or morepoles.

D represents a switch consisting of a base, (I, of insulating materialprovided with metallic contact-pieces (1 cf 9 and a metallic lever, 71,pivoted at 71 so that it can be moved into contact successively with thepieces (1 c f g. The terminals of the helices c c 0 lead, respectively,to the pieces (1 c f g, as shown, so that by moving the lever 71 intocontact with one of said pieces a portion of the field-magnet is cutout, substantially as described in my aforesaid appl icati on.

I K L M indicate resistancecoils, (for which, if desired, any othersuitable or equivalent form ot'rcsistance may be substituted,) whichare, respectively, of the same resistance as the m agnet-helices c c c,or suffieient, when thrown 1 into circuit, to compensate for theresistance I s I I of said helices when the latter are cut out. Theseresistance-coils are connected in series with metallic contact-pieces7|? I m n,with which the lever h may'also be brought into contact. Thecircuits are, as indicated in the drawing, the terminal of the wirexfrom thelower brush, N, leading to the contact-piece k, and the outerend of helix being connected with contact piece (Z.. The normal positionof parts is as shown in the drawing, in which case all of thefield-magnet coils are in circuit. 011 moving lever h so that its endsrest, respectively, on 1 pieces a and I, the helix 0 is cut out andresistance K thrown into circuit. By moving lever to stops f and m thetwo helices c and c are cut out and resistances K and L thrown in, and

indicates an electromotor, which may be of ture may be located androtate in the field of movement of said lever to stops 1 and n cuts outhelices c c c" and throws in resistances K,

. L, and M.

By connecting metallic contact-piece d with metallic pivot 71 by a wire,I, or by connecting wire with pivot 71", instead of contaetpiecc d, thehelices c c? 0 will be shunted instead of cut out oi oi cuit when lever7Fe ofita'e'tsv'itli metallic piece g, respectively.

"he metallic contact-pieces L (2 f y and k l m n can be close to eachother or so arranged that while lever h moves between any two of thesaid contact-pieces it will contact with both of them, therebyprevei'iting the main or exterior circuit being opened while lever I: isbeing moved between anytwo of said cont: :t-pieces.

Any other suitable switch may be employed, and in many cases it maybe-pret'erable to use one having a sliding device, moving like thesliding bolt 01' a wiinlow-shutter, and contacting with conductors orpieces (I c f g and 70 Z in a, or their equ' 'alent, for the purposehereinbe't'ore set forth.

My invention embraces any means whereby a diversion ol' the current froma portion or port-ions oi the magnet is effected, such portion orportions being either cut out or shunted by the provision of a new paththrough the magnet, such new path containing resistance equivalent tothe cut-out or shunted portion (ii-"portions of the magnet.

hat 1. claim as my invention is as follows:

1. The combination, with an electromotor constructed and provided withmeans for cut ting or shunting a portion of the coils oi." the'iield-magnm'v out of circuit, of means for introducing into theexterior circuit resistance equivalent to that of the coils cut out orshunt ed, substantially as shown and described.

2. The combination, with. an electromotor, of a switch or shuntingdevice having; a movable lever and contact-pieces with which theterminals of the coils of the :tiehl-magnet and resistances respectivelyconnect, whereby a movement of said switch will cut out or shuntaportion of the coils of said magnet and simultaneously introduce intothe circuit resistances equivalent to that oi the portion of the magnetcut out or shunted.

In testimony that 1'. claim the foregoing l have hereunto set my handthis 6th day of March, 1883.

- HENRY \V. SIAXG. \Vitnesses:

O. HOLTON, Isaac Y. Smxc.

